With a link structure of the delta-type，the steady-state mathematical model for DC side capacitor voltage is analyzed for cascaded H-bridge converters based on static synchronous compensator（STATCOM）.Special attention is paid to the influence of the voltage loop on the balanced and stable control strategy for the DC capacitor voltage.Meanwhile，strategies without a voltage inner loop and traditional voltage inner loop are researched in detail.On this basis，to achieve a slight phase shift of H-bridge modulated wave，a strategy for superposing the error signal by current feedback on the inverter side is proposed.The algorithm is simplified by forgoing the phase lock loop.Simulation results show that using the proposed control strategy，the DC capacitor voltage of H-bridges is stable and the steady-state error is reduced while STATCOM is used to compensate for reactive power and harmonic current.Finally，a cascaded STATCOM（660 V，300 kvar）experimental prototype is developed to analyze the compensation characteristics.The correctness and effectiveness of the strategy are confirmed.